Cardiac catheterisation measurements

Cardiac catheterisation is a procedure that is used to confirm a diagnosis of pulmonary hypertension (PH). Several measurements can be taken using a cardiac catheter (a long, thin, flexible tube inserted into a vein).

Measurements taken using a cardiac catheter

Measurement Definition Comment
Mean pulmonary artery pressure (mPAP) Average blood pressure in the main pulmonary arteries mPAP above 25mmHg while a person is resting indicates PH
Mean right atrial pressure (mRAP) Average blood pressure in the right atrium of the heart mRAP above 10mmHg indicates the heart is beginning to find it difficult to pump blood efficiently
Pulmonary capillary wedge pressure (PCWP or ‘wedge’) Estimation of the blood pressure on the left side of the heart (blood returning from the lungs to the heart) PCWP above 15mmHg indicates the heart is finding it hard to pump blood through the lungs
Cardiac output The amount of blood pumped through the heart in one minute PH causes reduced cardiac output
Pulmonary vascular resistance (PVR) The resistance the heart must pump against to force blood through the lungs PVR is normally higher in people with PH
Mixed venous oxygen saturation The amount of oxygen in the blood as it returns to the heart Gives an idea of how much oxygen a persons’ muscles and organs are extracting from the blood

Watch a video of a cardiac catheterisation, taken from the Pulmonary Hypertension Association (PHA UK) DVD Understanding Pulmonary Hypertension – a guide to diagnosis and treatment, here.


Last medically reviewed: January, 2019 • Due for review: January, 2022